A typical electronic system includes, among other things, (i) a frame, (ii) a power supply supported by the frame, and (iii) operating circuitry which is powered by the power supply and which is also supported by the frame. In some systems, the operating circuitry includes multiple circuit boards and an interconnection mechanism. The multiple circuit boards include integrated circuit devices (e.g., processors, application specific integrated circuits, discreet components, etc.) which derive power signals from the interconnection mechanism as well as exchange data signals through the interconnection mechanism.
One conventional interconnection mechanism includes a card cage and a backplane which mounts to a back end of the card cage. The backplane is essentially a large circuit board, i.e., a plane-shaped structure formed from layers of conductive material (e.g., copper) and non-conductive material (e.g., FR4) sandwiched together. The backplane typically has pads or power supply connectors on the side facing away from the card cage, and columns of backplane connectors on the side facing the card cage. To assemble the system, an installer connects the pads or power supply connectors of the backplane to the power supply using a set of cables, or directly plugs connectors of the power supply into connectors of the backplane. The installer also connects the circuit boards to the backplane by sliding the circuit boards into respective slots of the card cage until rows of circuit board connectors along the leading edges of the circuit boards connect with respective columns of backplane connectors on the backplane. At this point, the circuit boards are capable of obtaining power from the backplane as well as exchanging data signals with each other and perhaps other devices through the backplane.
As the complexity and operating speeds of circuit board components increase over time, so do the power demands of such components. As a result, there is a growing need for backplanes to provide power signals at higher currents to circuit boards (e.g., at many hundreds of Amps). Not only must backplanes be capable of obtaining these higher currents from the power supplies, backplanes must also be capable of distributing these higher currents reliably and robustly to the circuit boards at their respective connecting locations (i.e., to the respective columns of backplane connectors) without substantial signal degradation (e.g., with voltage drops along the backplane remaining within acceptable limits). To this end, there are a variety of conventional approaches that a manufacturer may use to increase the current distribution characteristics of a backplane design.
One conventional approach to increasing current distribution in a backplane design is for the manufacturer to increase the thicknesses of the power planes in the backplane design and/or the number of power planes in the backplane design. If the manufacturer increases the thickness of a power plane (e.g., from 1 oz. copper to 2 oz. copper), the power plane is now capable of carrying higher current. Similarly, if the manufacturer adds a power plane, the overall amount of current through the backplane increases. Thus, with thicker power planes and/or more power planes, the manufacturer successfully increases the current distribution characteristics of the backplane.
Another conventional approach to increasing current distribution in a backplane design is for the manufacturer to configure the outer side of the backplane with auxiliary power supply pads or connectors, and then attach metal busbars or cables to those pads or connectors to provide additional current paths along the backplane. The additional current carrying capacity provided by these metal busbars or cables prevents the voltage drop along the backplanes from falling outside of budgeted limits.